Abstract: A user of a management system, with which the user's reachability is managed, is assigned a reachability matrix in the system. This reachability matrix stores, in the form of reachability records, the respective reachability of the user via the communications media available to him in relation to a plurality of possible statuses. When events occur that result in a change of status with respect to the statuses recorded in the user's matrix, a reachability record of the user's matrix is defined as the actual reachability vector for the respective user on the basis of rules stored in the system, which reachability vector contains information for each medium available to the user for communication as to whether the user is at the moment to be reachable via the respective communications medium. For each communications medium affected by the change, the management system may generate control signals.